This invention relates to improvements in needle threading devices of the type having a needle threader member manually operable to displace a thread through the eye of a needle supported in the device.
Manually operable threading devices of the type to which the present invention relates are known, as shown for example in U.S. Pat. No. 2,679,959 to Von Ullisperger et al and Italian patent No. 488,887. Such devices include a housing, a needle support including an upwardly open cavity to receive and support the eye end of a needle, openings through the support transverse to the cavity and aligned with the eye of a needle therein, and a needle threader member supported in the housing for displacement through the openings and the needle eye to displace a thread through the needle eye, whereby the needle becomes threaded. In the Von Ullisperger et al device, the needle threader is pivotal relative to the housing and is displaced by a vertically reciprocable, spring biased camming plunger engaging a cam follower roller mounted on a lever supporting the needle threader member. In the Italian patent, the needle threader is horizontally reciprocable relative to the housing and has an outer end adjacent the housing to achieve such reciprocation.
In both of the needle threading devices referred to above, the needle threading operation requires breaking off a length of thread, displacing a portion of the thread between the ends thereof through the needle eye by actuation of the needle threader member, and displacing the needle and the length of thread in its entirety upwardly through the needle cavity by passage of the thread ends through the openings in the needle support and into the cavity. It is not possible, with these prior art arrangements, to separate the needle threader from a thread having one end essentially fixed against displacement through the openings in the needle support upon withdrawal of the threaded needle therefrom. For example, if a person is sewing a piece of material and accidentally displaces the needle from threaded engagement with the free end thereof, it is not possible to rethread the needle and thereafter achieve separation of the needle threader from the thread. In this respect, it will be appreciated that the end of the thread attached to the material being sewed is fixed with respect to the material, and the latter prevents displacement of the thread through the openings in the needle support upon removal of the threaded needle therefrom. Such accidental unthreading of a needle during sewing is a common occurrence and, in addition to the inconvenience of rethreading the needle by hand, such rethreading may be extremely difficult and perhaps even an impossible task for a person having poor eyesight and/or the inability to hold the needle and thread steady to achieve insertion of the thread through the needle eye.
Manually operable needle threaders of the character to which the present invention relates have enjoyed limited saleability heretofore, partially as a result of the foregoing limitations and inconvenience with respect to use thereof and partially because the cost of manufacture thereof has precluded an acceptable price in the market place. More particularly in this respect, the devices are relatively small and heretofore have required the assembly of a considerable number of individual component parts which are individually expensive to produce. In particular, the mechanisms heretofore provided for supporting and displacing the needle threader member have been structurally complex and unduly expensive in this respect. Moreover, hand assembly of all of the component parts is required, and the number and small size thereof makes such hand assembly a difficult and tedious endeavor requiring considerable time, thus undesirably adding to the expense of manufacture.